Methods for synthesizing a variety of different types of polymers are well known in the art. For example, the “Merrifield” method, described in Atherton et al., “Solid Phase Peptide Synthesis,” IRL Press, 1989, has been used to synthesize peptides on a solid support. In the Merrifield method, an amino acid is covalently bonded to a support made of an insoluble polymer or other material. Another amino acid with an alpha protecting group is reacted with the covalently bonded amino acid to form a dipeptide. After washing, the protecting group is removed and a third amino acid with an alpha protecting group is added to the dipeptide. This process is continued until a peptide of a desired length and sequence is obtained.
Methods have also been developed for producing large arrays of polymer sequences on solid substrates. These large “array” of polymer sequences have wide ranging applications and are of substantial importance to the pharmaceutical, biotechnology and medical industries. For example, the arrays may be used in screening large numbers of molecules for biological activity, i.e., receptor binding capability. Alternatively, arrays of oligonucleotide probes can be used to identify mutations in known sequences, as well as in methods for de novo sequencing of target nucleic acids.